Trends in the market for mobile broadband identify multimedia entertainment on wireless devices (e.g., smart phones, laptops) as one of the key drivers promoting the growth in higher data rates and improved user services. To support multimedia entertainment in next generation wireless systems, numerous wireless standards committees are promoting wireless standards that are optimized for the transmission of multimedia broadcast services. In the 3GPP standard, multimedia content is carried on Multimedia Broadcast Multicast Service (MBMS). In the 3GPP2 standard, multimedia content is carried on Broadcast Multicast Service (BCMCS). In the IEEE 802.16 standard, multimedia content is carried on Multicast Broadcast Service (MBS). The IEEE 802.16m standard, currently under development, is an enhanced update to the existing IEEE 802.16e standard. Consequently, the enhancements to MBS in IEEE 802.16m are termed Enhanced-MBS (E-MBS). Hereafter, E-MBS may be used generically to refer to MBS, E-MBS, and/or BCMCS.
There are differences in resource utilization in E-MBS transmissions and conventional base station-to-mobile station (BS-MS) unicast transmissions. A BS-MS unicast transmission is a transmission from the base station (or access point) to a given mobile station (e.g., smart phone, laptop, or other remote device) on the downlink (DL) or from the MS to the BS on the uplink (UL). Thus, the BS-MS link is a point-to-point link. As such, the signals from neighboring base stations are considered interference.
However, E-MBS transmissions, due to their broadcast nature, require that each BS transmits data to multiple user mobile stations. Thus, E-MBS is a point-to-multipoint link. However, the nature of E-MBS is such that the same data is transmitted from each base station to the mobile stations within the coverage area of each base station. Since the base stations are synchronized, the base stations transmit E-MBS data in a coordinated manner using the same set of resources, so that the E-MBS signals received by a mobile station from all neighboring base stations transmitting E-MBS data coherently add. Such a configuration is referred to as a single frequency network (SFN).
To support coordinated transmission of E-MBS data in a single frequency network, the resources selected for E-MBS transmissions across all cells must be the same. However, for unicast data, the resources must be randomized or permutated across the whole cell coverage area, so that the interference can be randomized and mitigated. Given the differences in the resource utilization, different resource partitioning schemes are used to support unicast and E-MBS transmissions. One such scheme separates E-MBS and unicast transmissions in time. Some time slots carry E-MBS data while other time slots carry unicast data. In this way, cell-specific permutations may be used for unicast data, while cell-common permutations are used for E-MBS data. Another scheme separates E-MBS data and unicast data by frequency, with some bandwidth allocated to E-MBS and other bandwidth allocated to unicast.
It is helpful to review the definitions of resource units and sub-channelization in the current IEEE 802.16m standards. To make resource utilization efficient, OFDM symbols are grouped to form a sub-frame. In IEEE 802.16m, six (6) OFDM symbols are used to form a regular sub-frame that is 0.625 milliseconds (ms) long. Eight (8) such regular sub-frames form a frame that is 5 milliseconds long. Four (4) frames make a super-frame (SF) that spans 20 milliseconds. To achieve granularity in resource utilization while keeping the signaling simple, the subcarriers in the OFDM symbols in a sub-frame are grouped to form resources. This portion of the time-frequency resource is sometimes called a resource block (RB) or a virtual resource block (VRB), a resource unit (RU) or a logical resource unit (LRU), or a resource channel (RCH). For the sake of convenience, this disclosure refers to a portion of the time-frequency resource as a resource unit (RU).
In IEEE 802.16m systems, a physical resource unit (PRU) is a rectangular tile made of eighteen (18) subcarriers in the frequency dimension and six (6) OFDM symbols in the time dimension. There are a total of NPRU PRUs over the entire bandwidth. For a 5 MHz system bandwidth, the value of NPRU=24. For 10 MHz, the value of NPRU=48 and for 20 MHz, the value of NPRU=96. Other RU sizes, such as 18 subcarriers by 7 OFDM symbols (18×7) or 18×5, allow flexibility for different system configurations.
There are different types of time-frequency RUs, such as a distributed logical resource unit (distributed LRU) and a localized logical resource unit (localized LRU) in IEEE 802.16m systems. These RUs may be allocated for transmitting data packets. The allocation of these RUs is communicated to mobile stations via signaling messages or control channel messages. In the downlink of an OFDMA system, for example, in addition to transmitting a data packet, a base station communicates to the targeted mobile station(s) information regarding the resources allocated to the transmission of the data packet, so that the targeted mobile station knows which RUs must be decoded to retrieve the data packet.
Furthermore, PRUs are categorized as sub-band PRUs and mini-band PRUs. To mitigate interference in the network, the PRUs are partitioned into different frequency partitions, where a re-use factor is used to reduce interference in each partition. The conventional partitioning of these resources is described in “Draft Amendment to IEEE Standard For Local And Metropolitan Area Networks; Part 16: Air Interface for Broadband Wireless Access Systems; Advanced Air Interface,” IEEE P802.16m/D1, July 2009, relevant excerpts of which are reproduced herein.
The number (K) of sub-bands (SB) in the ith frequency partition (FP) is denoted by KSB,FPi. The number (K) of mini-bands (MB) in the ith frequency partition (FP) is denoted by KMB,FPi. The size of the ith frequency partition is denoted by the field FPSi and the number of sub-bands in each frequency partition is denoted by the DFPSC field. Also, the number (L) of sub-band (SB) PRUs in the ith frequency partition is denoted by LSB,FPj and is given by Equation 1:LSB,FPi=N1KSB,FPi,  [Eqn. 1]
where N1=4.
The number (L) of mini-band PRUs in the ith frequency partition is denoted by LMB,FPi, and is given by Equation 2:LMB,FPi=N2KMB,FPi,  [Eqn. 2]
where N2=1.
The number of sub-bands for each frequency partition when FPCT=1 or FPCT=4 is given by Equation 3:
                              K                      SB            ,                          FP              i                                      =                  {                                                                                          K                    SB                                    -                                                            (                      FPCT                      )                                        ·                    FPSC                                                                                                i                  =                  0                                                                                    FPSC                                                              i                  >                  0.                                                                                        [                  Eqn          .                                          ⁢          3                ]            
When DFPC=1 and FPCT=3, the number of sub-bands in FPi (for i>0) is given by Equation 4:KSB,FPi=DFSPC.  [Eqn. 4]
The number of mini-bands for each frequency partition is given by Equation 5:
                                          K                          MB              ,                              FP                i                                              =                                                    FPS                i                            -                                                K                                      SB                    ,                                          FP                      i                                                                      ⁢                                  N                  1                                                                    N              2                                      ,                            [                  Eqn          .                                          ⁢          5                ]            
for 0≦i≦FPCT.
The mapping of sub-band PRUs and mini-band PRUs to the frequency partition i is given by Equation 6:
                                          PRU                          FP              i                                ⁡                      (            j            )                          ==                  {                                                                                                                PRU                      SB                                        ⁡                                          (                                              k                        1                                            )                                                        ,                                                                              0                  ≤                  j                  <                  FPCT                                                                                                                                                PPRU                      MB                                        ⁡                                          (                                              k                        2                                            )                                                        ,                                                                                                  L                                          SB                      ,                                              FP                        i                                                                              ≤                  j                  <                                                            (                                              L                                                  SB                          ,                                                                                    FP                              i                                                        +                                                          L                                                              MB                                ,                                                                  FP                                  i                                                                                                                                                                                        )                                        ′                                                                                                          [                  Eqn          .                                          ⁢          6                ]            
where:k1=Σm=0i−1LSB,FPm+j; andk2=Σm=0i−1LMB,FPm+j−LSB,FPi.
There are different resource partitioning requirements to support unicast and E-MBS data transmissions in a single frequency network. However, current proposals of the IEEE 802.16m standard do not support such single frequency network transmissions. Therefore, there is a need in the art for a resource partitioning scheme that supports unicast and E-MBS data transmissions in an IEEE 802.16m wireless network. In particular, there is a need for specific schemes for splitting available bandwidth between E-MBS data and unicast data.